Wheel center force test method
By examining the environmental disturbances and rotational order effects during operating condition testing on the test bench, more accurate environmental disturbance and rotational order effects were obtained, resulting in cleaner and more accurate operating condition response data.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SAIC GM WULING AUTOMOBILE CO LTD
- Filing Date
- 2026-01-27
- Publication Date
- 2026-05-12
AI Technical Summary
The existing technology suffers from low accuracy in wheel center force testing due to the single excitation method, incomplete transfer function representation, and significant interference from the working condition test environment.
Multiple actual excitation points are arranged around the wheel center virtual point in the brake disc or hub mounting area of the wheel. Excitation is performed using an excitation device, and excitation force signals and response signals are collected. Vibration and noise transfer function matrices are constructed and converted into transfer function matrices of the wheel center virtual point through a transformation matrix. Preset working condition tests are performed on a test bench, and the wheel center force is calculated using the inverse matrix method.
The accuracy of wheel center force testing was improved. By incorporating environmental disturbances and rotational order effects during pre-set operating condition tests on the test bench, purer and more accurate operating condition response data were obtained. Furthermore, by employing environmental disturbances and rotational order effects during cyclic operating condition tests, purer and more accurate working fluid response data were obtained.
Smart Images
Figure CN122016346A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of vehicle testing technology, specifically relating to a test method for wheel center force. Background Technology
[0002] Wheel center force is a key input excitation load in vehicle road noise simulation and an important parameter for tire selection in road noise development. Its testing accuracy has a significant impact on the development of vehicle road noise performance. Existing methods for obtaining wheel center force typically employ traditional wheel center force transfer path analysis (TPA) tests and indirectly obtain wheel center force through the inverse matrix method.
[0003] The experiment was mainly divided into two stages: the transfer function test stage and the operating condition test stage. In the transfer function test stage, an acceleration vibration sensor was placed at a location on the suspension steering knuckle that was not on the same plane. Microphones were placed near the ears of the driver and passengers inside the vehicle. A clamp was placed at the wheel rim and struck with a hammer to collect the vibration transmission frequency response function from the excitation point to the suspension steering knuckle and the noise transmission function from the excitation point to the microphone location inside the vehicle. In the operating condition test stage, the vehicle was driven to a rough road surface at the test track for operating condition testing. The vibration response of the acceleration vibration sensor on the steering knuckle and the noise response of the microphone inside the vehicle were collected under the corresponding operating conditions. During this process, it was difficult to ensure that the magnitude and direction of the excitation force applied by the hammer were consistent, introducing additional human and random errors. Furthermore, operating condition testing on actual road surfaces was subject to numerous external interference factors, affecting the accuracy of the response data.
[0004] The calculation and verification process of wheel center force is as follows: First, the wheel center force of the four wheels is calculated by using the inverse matrix method from the transfer function of the vibration sensor on the suspension steering knuckle from the excitation point and the acceleration vibration response data on the steering knuckle. Then, based on the linear time-invariant system assumption and the superposition principle, the wheel center forces of the four wheels and the noise transfer function data from the wheel center to the microphone position inside the vehicle are multiplied and linearly superimposed in the frequency domain to fit the noise response at the microphone position inside the vehicle. According to the linear time-invariant system assumption, the fitted in-vehicle noise response should be consistent with the in-vehicle noise response tested under actual working conditions. The accuracy of wheel center force acquisition can be judged by comparing the degree of consistency between the two. The method of obtaining the transfer function by striking the wheel rim with a single-point hammer is difficult to accurately and comprehensively characterize the vibration transmission characteristics from the wheel center to the complex suspension system. Therefore, the accuracy of the transfer function test is limited, resulting in low accuracy of the acquired wheel center force, which is insufficient to meet the requirements of high-precision development. The comparison curves of the in-vehicle noise response tested and fitted by the existing technology and the in-vehicle noise response tested under actual working conditions are shown below. Figure 1 As shown, Figure 1 The red curve represents the measured response value, and the blue curve represents the fitted value. This is from... Figure 1The results show that the two curves have a large difference in consistency in the low-frequency range, which indirectly indicates that the accuracy of the wheel center force obtained by the existing testing technology is not high.
[0005] In summary, how to overcome the problems of low wheel center force testing accuracy caused by the single excitation method, incomplete transfer function representation, and large interference from the working condition testing environment in traditional testing methods, and thus obtain high-precision wheel center force data, has become an urgent technical problem to be solved in this field. Summary of the Invention
[0006] The purpose of this application is to solve the problems existing in the prior art and provide a test method for wheel center force, which effectively solves the problem of low wheel center force test accuracy caused by single excitation method, incomplete transfer function representation and large interference in working condition test environment in traditional test methods, thereby obtaining high-precision wheel center force data.
[0007] This application is achieved through the following technical solution:
[0008] This application provides a method for testing the wheel center force, the method comprising: In the brake disc or hub mounting area of the wheel, multiple actual excitation points are arranged around the virtual point of the wheel center; The excitation device is used to excite each of the actual excitation points in sequence, and the excitation force signal, the vibration response signal of each response point on the vehicle suspension steering knuckle, and the noise response signal of the noise measurement point in the vehicle interior are collected. Based on the excitation force signal and the vibration response signal, the vibration transfer function matrix from each actual excitation point to each response point is obtained; based on the excitation force signal and the noise response signal, the noise transfer function matrix from each actual excitation point to the noise measurement point inside the vehicle is obtained. Based on the spatial coordinate relationship between the virtual wheel center point and each of the actual excitation points, a transformation matrix is constructed. The vibration transfer function matrix and the noise transfer function matrix are then converted into the vibration transfer function matrix from the virtual wheel center point to the response point and the noise transfer function matrix from the virtual wheel center point to the noise measurement point inside the vehicle, respectively. The vehicle was tested under preset working conditions on the test bench, and vibration response data of the response points and noise response data of the noise measurement points in the vehicle interior were collected under the preset working conditions. Based on the vibration transfer function matrix from the virtual wheel center point to the response point and the vibration response data under the preset working conditions, the wheel center force acting on the virtual wheel center point is obtained by the inverse matrix method.
[0009] Optionally, multiple actual excitation points are arranged around a virtual point at the wheel center in the brake disc or hub mounting area, including: Design and install multiple excitation fixtures onto the wheel mounting screws of the brake disc, each of the excitation fixtures having multiple excitation positions defined in multiple directions, the multiple directions corresponding to the three orthogonal axes of the vehicle.
[0010] Optionally, the number of the excitation fixtures is five, and each excitation fixture has three excitation positions defined, forming a total of fifteen actual excitation points.
[0011] Optionally, the excitation device is a miniature vibrator.
[0012] Optionally, the transformation matrix is constructed based on coordinate transformation and modal coordinate transformation methods, and is used to establish a mathematical mapping relationship between the excitation force at the virtual point of the wheel center and the excitation force at each of the actual excitation points.
[0013] Optionally, the vehicle is tested under preset operating conditions on a test bench, and vibration response data of the response points and noise response data of the noise measurement points inside the vehicle are collected under the preset operating conditions, including: The vehicle is placed on a full-vehicle drum test bench, and the rough surface of the drum is used to simulate the road surface's excitation on the vehicle. The vehicle is controlled to perform uniform acceleration and uniform deceleration cycles, and vibration response data of the response points and noise response data of the noise measurement points inside the vehicle are collected during the cycle.
[0014] Optionally, the uniform acceleration and deceleration cycle is: to make the vehicle accelerate and decelerate uniformly within a preset range above and below the reference speed value, and repeat this cycle multiple times.
[0015] Optionally, the reference speed is 60 km / h, the range is 5% above and below the reference speed, and the number of cycles is 2 to 3.
[0016] Optionally, the test method further includes: The theoretical response data of the vehicle interior noise is synthesized using the calculated wheel center force and the noise transfer function matrix from the virtual point of the wheel center to the noise measurement point inside the vehicle. The accuracy of the wheel center force is evaluated by comparing the theoretical response data with the measured noise response data and assessing their consistency.
[0017] Optionally, the number of response points arranged on the suspension steering knuckle is greater than or equal to five, and the positions of each response point are not coplanar.
[0018] Compared with existing technologies, the beneficial effects of this application are as follows: By arranging multiple actual excitation points around a virtual point at the wheel center and performing coordinate transformation, this application can obtain a richer and more accurate frequency response function that characterizes the complex transmission path from the wheel center to the suspension system than the traditional single-point excitation method, fundamentally improving the test accuracy of the transfer function; by setting the preset working condition test on the test bench and using cyclic working conditions, the environmental interference and rotation order influence of outdoor road testing are effectively eliminated, resulting in purer and more accurate working condition response data. Due to the above two points, the accuracy of the wheel center force data calculated by the inverse matrix method is significantly improved, providing a more reliable input load for vehicle road noise simulation and development, and improving the efficiency and accuracy of noise, vibration and harshness (NVH) performance development. Attached Figure Description
[0019] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The accompanying drawings are used to provide a further understanding of the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof.
[0020] Figure 1 This is a comparison curve of the in-vehicle noise response tested and fitted using existing technology and the in-vehicle noise response tested under actual operating conditions. Figure 2 A schematic flowchart illustrating a method for testing the wheel center force according to an embodiment of this application; Figure 3 A schematic diagram of the excitation point arrangement provided in the embodiments of this application; Figure 4a A comparison curve of the measured response at the driver's right ear position in the front row of the vehicle and the fitted response using existing methods; Figure 4b This is a comparison curve of the measured response at the right ear position of the driver in the front seat of the vehicle and the fitted response of the method in the embodiment of this application.
[0021] Explanation of reference numerals in the attached figures: 1—Brake disc, 2—Excitation fixture, 3—X, Y, Z excitation positions, 4—Virtual excitation point at the wheel center. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of this application more apparent, exemplary embodiments according to this application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein. Based on the embodiments of this application described herein, all other embodiments obtained by those skilled in the art without inventive effort should fall within the protection scope of this application.
[0023] To address the low accuracy of wheel center force testing in existing methods due to their simplistic excitation methods, incomplete transfer function representation, and significant interference from the testing environment, this application proposes a new method for testing wheel center force. This method effectively improves the accuracy of wheel center force testing and can be used for the development of vehicle NVH performance. The following is a further detailed description of this application with reference to the accompanying drawings.
[0024] Figure 1 This is a flowchart illustrating a method for testing the wheel center force according to an embodiment of this application. The following first refers to... Figure 1 This application describes a method for testing the wheel center force according to an embodiment of the present application.
[0025] like Figure 1 As shown, the wheel center force test method in this application includes at least the following steps S100 to S600.
[0026] Step S100: Arrange multiple actual excitation points around the virtual point of the wheel center in the brake disc or hub mounting area of the wheel.
[0027] The virtual point at the wheel center refers to a theoretically defined point at the center of the wheel, which is the point of application of the wheel center force to be solved. Because this point is in a confined space or cannot be directly fitted with a sensor, it is called a virtual point.
[0028] Step S200: Use the excitation device to excite each actual excitation point in sequence, and collect the excitation force signal, the vibration response signal of each response point on the vehicle suspension steering knuckle, and the noise response signal of the noise measurement point in the vehicle interior.
[0029] The actual excitation point refers to a physical location in the wheel brake disc or hub mounting area that is convenient for installing an excitation device and performing vibration. These points surround the virtual point at the wheel center. The excitation device refers to the equipment used to apply a controllable excitation force, such as a miniature vibrator, which, unlike a traditional force hammer, can provide a more stable and consistent excitation.
[0030] Step S300: Based on the excitation force signal and vibration response signal, obtain the vibration transfer function matrix from each actual excitation point to each response point; based on the excitation force signal and noise response signal, obtain the noise transfer function matrix from each actual excitation point to the noise measurement point inside the vehicle.
[0031] The vibration transfer function matrix describes the set of frequency-domain mathematical relationships of vibration transmission characteristics from the excitation point to each response point on the suspension steering knuckle; it is a multi-input multi-output matrix. The noise transfer function matrix describes the set of frequency-domain mathematical relationships of sound transmission characteristics from the excitation point to each noise measurement point inside the vehicle.
[0032] Step S400: Based on the spatial coordinate relationship between the virtual wheel center point and each actual excitation point, construct a transformation matrix. Use the transformation matrix to convert the vibration transfer function matrix and the noise transfer function matrix into the vibration transfer function matrix from the virtual wheel center point to the response point and the noise transfer function matrix from the virtual wheel center point to the noise measurement point inside the vehicle, respectively.
[0033] The transformation matrix is a mathematical matrix constructed based on spatial coordinate relationships and mechanical principles (such as rigidity assumptions or modal coordinate transformations). It is used to equivalently map forces acting on multiple actual excitation points to forces and torques (six components) on a virtual point at the wheel center, or to transform the transmission characteristics of actual points to virtual points.
[0034] Step S500: Conduct a preset working condition test on the vehicle on the test bench, and collect vibration response data of the response points and noise response data of the noise measurement points in the vehicle interior under the preset working conditions.
[0035] Test benches refer to indoor testing equipment used to simulate vehicle driving conditions, such as whole vehicle drum test benches, whose drum surfaces can simulate rough road surfaces, and whose testing environment (such as semi-anechoic chambers) is controllable. Preset condition testing refers to standardized driving tests designed to obtain the load input of wheel center force; in this application, it specifically refers to the slow-speed cyclic condition test conducted on a test bench.
[0036] Step S600: Based on the vibration transfer function matrix from the virtual wheel center point to the response point and the vibration response data under the preset working conditions, the wheel center force acting on the virtual wheel center point is calculated by the inverse matrix method.
[0037] Among them, the inverse matrix method is a calculation method that, when the system output and system characteristics are known, inversely deduce the system input by solving matrix equations. Specifically, in this application, the inverse matrix method is used to inversely deduce the wheel center force by solving matrix equations (usually by finding the generalized inverse) when the operating condition response and transfer function matrix are known.
[0038] This application, by arranging multiple actual excitation points around a virtual point at the wheel center and performing coordinate transformation, can obtain a richer and more accurate frequency response function that characterizes the complex transmission path from the wheel center to the suspension system than the traditional single-point excitation method, fundamentally improving the test accuracy of the transfer function. By setting the preset working condition test on a test bench (such as a vehicle drum) and using cyclic working conditions, the environmental interference and rotation order influence of outdoor road testing are effectively eliminated, resulting in cleaner and more accurate working condition response data. Due to the above two points, the accuracy of the wheel center force data calculated by the inverse matrix method is significantly improved, providing a more reliable input load for vehicle road noise simulation and development, and improving the efficiency and accuracy of noise, vibration and harshness (NVH) performance development.
[0039] The following will describe in detail, with reference to the accompanying drawings and specific embodiments, a method for testing wheel center force provided in this application.
[0040] Example 1 This embodiment provides a complete method for testing the wheel center force, such as... Figure 3 The diagram showing the arrangement of excitation points illustrates the method, which includes the following steps: S101. Arrange the actual stimulus points and response points.
[0041] Since the wheel center position is inconvenient for excitation, the wheel center position is defined as a virtual excitation point 4 in the brake disc 1 mounting area. Multiple (e.g., 15) actual excitation points are arranged around this theoretical virtual excitation point 4. Specifically, five excitation fixtures 2 are designed and fabricated, and installed on the wheel mounting screws of the brake disc 1. Each excitation fixture 2 defines three excitation positions 3 in orthogonal directions (parallel to the X, Y, and Z directions of the vehicle coordinate system), thus forming multiple actual excitation points around the virtual wheel center point in space.
[0042] Meanwhile, three-dimensional acceleration vibration sensors are placed at five non-coplanar locations on the suspension steering knuckle of each wheel as vibration response points. Microphones are placed near the ears of occupants inside the vehicle (such as the driver's right ear and the passenger's left ear) as noise measurement points.
[0043] S102, Test the transfer function.
[0044] A miniature exciter is used as the excitation device and is sequentially installed at each actual excitation point location defined in step S101 for excitation. The excitation force signal at each excitation point is synchronously collected via a data acquisition system. F Three-dimensional vibration response signals at all steering knuckle response points A and the noise response signals of all in-vehicle noise measurement points.P n .
[0045] According to linear system theory, the relationship between excitation force, transfer function, and response is as follows: (1) (2) in,[ A ] is a matrix (i×1 dimension) composed of the responses at all vibration points. P n [ is a matrix composed of the responses of all noise measurement points,] F ] is a matrix (j×1 dimension) composed of various actual excitation forces. H Let ] be the vibration transfer function matrix (i×j dimensions) from the actual excitation point to the steering knuckle response point, [ H n [I] represents the noise transfer function matrix from the actual excitation point to the noise measurement point inside the vehicle, where i is the number of vibration response points on the steering knuckle and j is the number of actual excitation points.
[0046] By repeatedly exciting and collecting data, the vibration transfer function matrix from each actual excitation point to the response point on the suspension steering knuckle can be obtained. H [and the noise transfer function matrix from each actual excitation point to the response point near the ear of the passenger inside the vehicle] Hn ].
[0047] Compared to the traditional method of placing a clamp at the rim and using a hammer to excite it, this solution innovatively uses a micro exciter for excitation. The micro exciter has better consistency in the magnitude and direction of the excitation force, and the excitation force data obtained is more accurate. As a result, the transfer function from the wheel center to the suspension system is richer and can better characterize the transmission characteristics of the suspension system.
[0048] S103. Construct the transformation matrix and transform the transfer function to the virtual point of the wheel center.
[0049] The construction principle of the transformation matrix will be explained first below.
[0050] For a linear time-invariant system with N degrees of freedom, its equations of motion are: (3) Where M, C, and K are the N×N dimensional mass matrix, damping matrix, and stiffness matrix of the system, respectively; X and F are the displacement and excitation force vectors (N×1 dimensional) of the system, respectively.
[0051] Using the modal superposition method, physical coordinates x(t) can be transformed into modal coordinates q(t): (4) Where x(t) is the response vector in physical coordinates (including all actual physical measurement points); It is the modal shape matrix (an N × m matrix), each column is a first-order modal shape vector, and m is the number of modes intercepted (m ≤ N); q(t) is the modal coordinate vector (an m × 1 matrix).
[0052] Substituting equation (4) into (3) and utilizing the orthogonality of modes, the original coupled equations can be decoupled into m independent single-degree-of-freedom equations: (5) in, , , These are the natural frequency, damping ratio, and modal mass of the r-th mode, respectively.
[0053] We now divide all degrees of freedom into two groups: one group represents the degrees of freedom where the physical measurement points of the actual sensor placement are located, and the other group consists of n. a The other group represents the degrees of freedom of the virtual measuring points, with a quantity of n. v And n a +n v =N. Correspondingly, the displacement vector and mode shape matrix can be divided into blocks as follows: (6) (7) in, It is the response of the physical measuring point (n) a (×1 dimension) The response of the virtual measurement point (n) v (×1 dimension) It is the submatrix (n) of the mode shape at the physical measurement point. a (×m dimensions) It is the submatrix (n) of the mode shape at the virtual measurement point. v (×m dimensions).
[0054] According to the principle of modal superposition, we have: (8) Equation (8) is a system of linear equations, which can be derived from known quantities. The modal coordinates q(t) are determined by measurement. Since the number of physical measurement points may not equal the number of modes, the least squares method is used to find the optimal solution to the equation to suppress the influence of measurement noise. Therefore: q (9) matrix for The false reversal is denoted as Equation (9) can then be written as: q (10) The response of the virtual measuring point can be calculated using the following formula: (11) Therefore, the transformation matrix T from the actual physical measurement point to the virtual measurement point can be obtained. va : (12) T va It is a constant matrix that can be calculated once the modal shapes of the structure and the locations of the physical measurement points are determined.
[0055] Since the wheel center position cannot be directly excited, the measured transfer function from the actual excitation point needs to be transformed to the virtual point at the wheel center. The excitation force of each actual excitation point constitutes the actual excitation force matrix [F] (N×1 dimension); in the digital model of the brake disc and excitation fixture, the spatial coordinates of the virtual point at the wheel center and the spatial coordinates of each actual excitation point are accurately measured; referring to the above derivation process of the transformation matrix, a transformation matrix [T] is constructed to transform the excitation force of each actual excitation point to the excitation force of the virtual point at the wheel center. After the transformation, the response result of the excitation of the virtual point at the wheel center is equivalent to the response result of the excitation of each actual excitation point.
[0056] The converted excitation force acting on the virtual point of the wheel center [ F v The force transformation matrix [T] and the actual excitation force matrix [F] can be expressed as follows: [ F v ]=[ T ][ F (13) in,[ F v The force transformation matrix [T] is a 6×1 dimensional matrix, and the force transformation matrix [T] is a 6×j dimensional matrix, which can be represented as: (14) in, R jX , R jY , R jZ These are the X, Y, and Z coordinates of point j, with the virtual point at the wheel center as the origin. I jX , I jY , I jZ These represent the directional projections of the force vector acting at point j onto the X, Y, and Z coordinate axes, respectively.
[0057] The force at the virtual point of the wheel center, the transfer function from the virtual point to each response point, and the relationship of the responses can be expressed in matrix form as follows: [ A ]= [ H v ] [ F v (15) Where [A] is the response matrix composed of responses, [ H v [ is the transfer function matrix consisting of the transfer functions from the virtual point at the wheel center to the steering knuckle response point, [ F v [ ] is the force matrix composed of various actual excitation forces.
[0058] Substituting equation (13) into equation (15), we get: [ A ]= [ H v [T][F](16) Furthermore, using the transformation matrix, the measured transfer function matrix can be equivalently transformed to the virtual point at the wheel center: [ H v ]=[ T ] + [ H (17) [ H nv ]=[ T ] + [ H n (18) in,[ T ] + It is a transformation matrix [ T The generalized inverse matrix of . H n [ ] is the noise transfer function matrix from the actual excitation point to the noise measurement point inside the vehicle. H nv [ ] is the noise transfer function matrix from the virtual point at the wheel center to the noise measurement point inside the vehicle.
[0059] S104. Conduct preset working condition tests.
[0060] To address the issue of interference from road surface debris during actual test road testing, and to utilize the fact that a rough road surface can also excite the low-frequency characteristics (below 300Hz) of the vehicle road noise, this embodiment conducts operating condition tests in a controlled indoor environment. The vehicle is placed on a vehicle drum test bench in a semi-anechoic chamber, with the drum surface simulating a rough road surface, in order to obtain operating condition response data with a high signal-to-noise ratio.
[0061] The preset operating condition is a gradual speed change cycle: the vehicle is controlled to accelerate uniformly from 57 km / h to 63 km / h, and then decelerate uniformly back to 57 km / h, repeating this acceleration-deceleration process 2 to 3 times. This design can effectively stimulate the low-frequency road noise characteristics of the vehicle and eliminate the interference of the drum rotation order noise through non-steady-state operation. During this process, vibration response data [A1] of each response point on the steering knuckle and noise response data [P1] of each noise measurement point inside the vehicle are collected by vibration sensors.
[0062] This technical solution utilizes the characteristic that a rough road surface can excite the low-frequency road noise characteristics of a vehicle even when the drum is in operation. By designing a gradual speed change test (within a 5% fluctuation range of the constant speed test value), the influence of the drum's rotational order on the test results is eliminated. Therefore, performing the gradual speed change test on the vehicle drum is equivalent to performing a constant speed test at 60 km / h on an actual test road. Using this test solution results in less external interference and more accurate test data.
[0063] S105, Calculate the wheel center force.
[0064] Based on the principle of the inverse matrix method, the vibration transfer function matrix of the wheel center virtual point obtained in step S103 is used [ H v The vibration response under the operating condition obtained in step S104 A 1], thus the wheel center force acting on the virtual point of the wheel center can be calculated. F v ]: [ F v ]=[ H v ] + [ A 1](19) in,[ H v ] + It is a matrix [ H v The generalized inverse matrix of ].
[0065] In a preferred embodiment, the test method further includes step S106, verifying the accuracy of the wheel center force results.
[0066] The wheel center force of the four wheels [F] v [The noise transfer function matrix from the corresponding wheel center to the microphone position inside the vehicle] H nvThe noise responses of each transmission path from the wheel center to the microphone position inside the vehicle are multiplied separately to obtain the noise response of each transmission path. The noise responses of each transmission path are then linearly superimposed in the frequency domain to fit the total noise response P2 at the occupant's ear. The consistency between the fitted noise response P2 and the actual noise response P1 at the occupant's ear obtained under actual operating conditions is compared to determine the accuracy of wheel center force acquisition.
[0067] Figure 4a A comparison curve of the measured response at the driver's right ear position in the front seat of the vehicle and the fitted response using existing methods. Figure 4b This is a comparison curve of the measured response at the driver's right ear position in the front seat of the vehicle and the fitted response of the method in the embodiments of this application; where the red curve is the measured response curve and the blue curve is the fitted response curve, as shown in the figure. Figure 4a and Figure 4b As shown in the curve, after adopting the method of this embodiment, the theoretical fitting curve (blue) and the measured curve (red) are closer in the key low frequency range of 20-200Hz, and the consistency is much better than that of the traditional method, thus confirming that the wheel center force data obtained by this method is more accurate.
[0068] After verification, if the fitting accuracy meets the usage requirements, high-precision wheel center force data can be exported.
[0069] Example 2: Specific arrangement of excitation points.
[0070] This embodiment is a further refinement of step S101 in embodiment 1.
[0071] Multiple actual excitation points are arranged in the following way: Five identical metal excitation fixtures are designed, each with a threaded hole at its bottom that matches the wheel mounting screw of the brake disc. These screws rigidly connect the fixture to the brake disc. Each fixture is a polyhedral structure with standard interfaces machined on its three mutually perpendicular outer surfaces for mounting miniature exciters. These three interfaces correspond to the X-axis (front-to-back), Y-axis (left-to-right), and Z-axis (up-down) of the vehicle, respectively. These five fixtures provide a total of fifteen actual excitation points with clearly defined directions and fixed positions. These points are evenly distributed in space, effectively stimulating the dynamic characteristics of the suspension system.
[0072] Finally, it should be noted that the above technical solution is only one implementation method of this application. For those skilled in the art, based on the application methods and principles disclosed in this application, it is easy to make various types of improvements or modifications, and not limited to the methods described in the specific implementation methods above. Therefore, the methods described above are only preferred and have no limiting significance.
Claims
1. A method for testing the wheel center force, characterized in that, The test method includes: In the brake disc or hub mounting area of the wheel, multiple actual excitation points are arranged around the virtual point of the wheel center; The excitation device is used to excite each of the actual excitation points in sequence, and the excitation force signal, the vibration response signal of each response point on the vehicle suspension steering knuckle, and the noise response signal of the noise measurement point in the vehicle interior are collected. Based on the excitation force signal and the vibration response signal, the vibration transfer function matrix from each actual excitation point to each response point is obtained; based on the excitation force signal and the noise response signal, the noise transfer function matrix from each actual excitation point to the noise measurement point inside the vehicle is obtained. Based on the spatial coordinate relationship between the virtual wheel center point and each of the actual excitation points, a transformation matrix is constructed. The vibration transfer function matrix and the noise transfer function matrix are then converted into the vibration transfer function matrix from the virtual wheel center point to the response point and the noise transfer function matrix from the virtual wheel center point to the noise measurement point inside the vehicle, respectively. The vehicle was tested under preset working conditions on the test bench, and vibration response data of the response points and noise response data of the noise measurement points in the vehicle interior were collected under the preset working conditions. Based on the vibration transfer function matrix from the virtual wheel center point to the response point and the vibration response data under the preset working conditions, the wheel center force acting on the virtual wheel center point is obtained by the inverse matrix method.
2. The method for testing the wheel center force according to claim 1, characterized in that, In the brake disc or hub mounting area of the wheel, multiple actual excitation points are arranged around the virtual point at the wheel center, including: Design and install multiple excitation fixtures onto the wheel mounting screws of the brake disc, each of the excitation fixtures having multiple excitation positions defined in multiple directions, the multiple directions corresponding to the three orthogonal axes of the vehicle.
3. The method for testing wheel center force according to claim 2, characterized in that, The number of the excitation fixtures is five, and each excitation fixture has three excitation positions defined, forming a total of fifteen actual excitation points.
4. The method for testing wheel center force according to claim 1, characterized in that, The excitation device is a miniature vibrator.
5. The method for testing the wheel center force according to claim 1, characterized in that, The transformation matrix is constructed based on coordinate transformation and modal coordinate transformation methods, and is used to establish a mathematical mapping relationship between the excitation force at the virtual point of the wheel center and the excitation force at each of the actual excitation points.
6. The method for testing the wheel center force according to claim 1, characterized in that, The vehicle was tested under preset operating conditions on a test bench, and vibration response data at the response points and noise response data at noise measurement points inside the vehicle were collected under the preset operating conditions, including: The vehicle is placed on a full-vehicle drum test bench, and the rough surface of the drum is used to simulate the road surface's excitation on the vehicle. The vehicle is controlled to perform uniform acceleration and uniform deceleration cycles, and vibration response data of the response points and noise response data of the noise measurement points inside the vehicle are collected during the cycle.
7. The method for testing wheel center force according to claim 6, characterized in that, The uniform acceleration and deceleration cycle is as follows: the vehicle accelerates and decelerates uniformly within a preset range above and below the reference speed value, and this cycle is repeated multiple times.
8. The method for testing wheel center force according to claim 7, characterized in that, The reference speed is 60 km / h, the range is 5% above and below the reference speed, and the number of cycles is 2 to 3.
9. The method for testing the wheel center force according to claim 1, characterized in that, The test method also includes: The theoretical response data of the vehicle interior noise is synthesized using the calculated wheel center force and the noise transfer function matrix from the virtual point of the wheel center to the noise measurement point inside the vehicle. The accuracy of the wheel center force is evaluated by comparing the theoretical response data with the measured noise response data and assessing their consistency.
10. The method for testing the wheel center force according to claim 1, characterized in that, The number of response points arranged on the suspension steering knuckle is greater than or equal to five, and the positions of each response point are not coplanar.